The ion-conductive ceramic membranes are nowadays under intense investigation to increase their performances; they find particularly interesting applications in the following fields of:                high-temperature water electrolysis for the production of hydrogen,        the manufacture of hydrogen fuel cells,        separation and purification of hydrogen and its isotopes in comparison with carbon-based products.        
Today, hydrogen (H2) appears to be a very interesting energetic vector, which should become more and more important for the treatment of, among others, petroleum products, and could eventually favourably replace petroleum and fossil energies, whose stocks will strongly decrease over the next decades. In this perspective, it is, however, necessary to develop efficacious methods for hydrogen preparation.
Although numerous methods have been described for the synthesis of hydrogen from different sources, most of these methods are indeed not well adapted to the massive industrial production of hydrogen.
In this context, it can be mentioned, for example, the synthesis of hydrogen from hydrocarbons. One of the major problems of this synthetic route is that it produces, as by-products, important quantities of greenhouse gas, such as CO2. In fact, currently, to produce 1 ton of hydrogen, 8 to 10 tons of CO2 are released.
Methods for thermochemical conversions of water into hydrogen can also be mentioned, most of which cannot be transposed to industrial scale, in particular, the direct thermal decomposition of water, which would require unrealistic temperatures of about 3000 to 4000° K., which can, however, be reduced in the presence of catalysts.
Other types of thermochemical decompositions of water from sulfur, iodide or bromide catalysts require lower temperatures of 850° C. but induce severe corrosion problems avoiding their industrialisation.
The most promising route for the industrial production of hydrogen is the technique based on high-temperature steam electrolysis (known as HTE).